Justification:
Long-term monitoring indicates that this species is undergoing severe fluctuations, primarily as a result of marine perturbations that may be becoming more extreme. These perturbations have caused an overall very rapid population reduction over the last three generations (34 years). In addition, it has a small population, and is restricted to a very small range, with nearly all birds breeding at just one location. These factors qualify it as Endangered.

Spheniscus mendiculus is endemic to the Galápagos Archipelago, Ecuador where its population is thought to number fewer than 2,000 individuals. Approximately 95 % of the Galápagos Penguin's population is found on Isabela and Fernandina Islands in the western part of the archipelago, with the remaining 5 % on Bartolomé, Santiago, Logie and Floreana Islands in the central-south area of the archipelago (Jiménez-Uzcátegui et al. 2006, Vargas et al. 2007). Analysis of mark-recapture results indicates that past population estimates were too high. In 1971, 1,931 penguins were counted, equating to a population of 3,400 individuals (Boersma 1998). The 1982-1983 El Niño Southern Oscillation (ENSO) reduced the population by 77%. After this, the population entered a slow recovery phase. However, the 1997-1998 ENSO induced a further decline of 66% (Mills and Vargas 1997, Boersma 1998, Ellis et al. 1998). Although the annual penguin census shows a relatively stable and even slightly increasing population trend over the last nine years, the current small population size (1,009 individuals counted in 2007) represents only a small fraction of that in the 1970s (Vargas et al. 2005, Jiménez-Uzcátegui et al. 2006, Vargas et al. 2007). The main breeding range stretches along the coast of the two westernmost islands, encompassing approximately 402 km of coastline, where 96% of all nests are found (Steinfurth 2007).

Located on the equator, the Galápagos Penguinrepresents the most northerly breeding penguin species. Nonetheless, its distribution is highly linked to the cool and nutrient-rich oceanic waters in the western archipelago that allows for a high density of prey year-round (Palacios et al. 2006). It nests at sea-level, and appears to forage close to shore and at relatively shallow depths (Mills and Vargas 1997, Steinfurth et al. 2008). Galápagos Penguins breed throughout the year, with two marked peaks from March to May and from July to September coinciding with variation in the upwelling (Steinfurth 2007). Recent studies show that during chick-rearing adult birds move up to 23.5 km from the nest, concentrating foraging within 1 km of the shore (Steinfurth et al. 2007). While breeding Galápagos Penguins show a high site-fidelity (>80%), non-breeding Galápagos Penguins (adults and juveniles) tend to migrate away from their colony (max. 64 km) (Steinfurth 2007).

In recent decades, this species has been influenced primarily by the effects of ENSO on the availability of shoaling fish (Boersma 1998, Vargas et al. 2007). This had been most evident in 1982-83 and 1997-98, when the penguin population underwent dramatic declines of 77 % and 65 %, respectively. After this, the population entered a slow recovery phase and annual penguin censuses indicate a relatively stable, and even slightly increasing, population trend over the last nine years, however the current population size is still 48 % below the pre-El Niño population levels (Mills and Vargas 1997, Boersma 1998, Ellis et al. 1998, Jiménez-Uzcátegui et al. 2006, Vargas et al. 2007). Recovery from the 1982-1983 ENSO may have been slowed by the lower frequency of La Niña cold water events and above average surface water temperatures (Boersma 1998). Also, ENSO may have a disproportionate impact on females, which could result in a biased sex ratio, making population recovery slower (Boersma 1998). Climate change may lead to an increase in the frequency of ENSO events in the future, which will also reduce the species's resilience to other threats such as disease outbreaks, oil spills, or predation by introduced predators (Boersma 1998, Boersma et al. 2005, Steinfurth and Merlen 2005, Travis et al. 2006, Vargas et al. 2007). Local fishing boats operating in inshore waters in the western part of the archipelago are documented as incidentally drowning Galápagos Penguins due to floating nets and illegally-used bait fisheries in gill nets (Cepeda and Cruz 1994, Simeone et al. 1999). Recent plans to establish longline fisheries in the Galápagos raises additional concern. Aside from the impact of by-catch caused by this technique (Weimerskirch et al. 2000), in the case of Galápagos Penguins, it is likely that an increasing demand for bait fish will dramatically increase inshore bait fisheries with all its associated problems. Contamination from oil spills poses a severe potential threat. Predation by introduced cats (Felis catus) on the Galápagos Penguin population at its main breeding site resulted in adult mortality of 49 % per year (Steinfurth 2007). feral cats are also vectors of parasites, such as Toxoplasma gondii, which has recently been found in Galapagos penguins (Deem et al. 2010). Mosquitoes (Culex quinquefasciatus) arrived on the Galápagos in the 1980s as a result of human actions. Since they are vectors for avian malaria, and penguins in the genus Spheniscus are highly susceptible to this disease these insects represent a potential new threat for the penguins (Travis et al. 2006). Indeed, the Plasmodium blood parasite has recently been recorded in Galapagos penguins for the first time (Levin et al. 2009). Many of the above threats are exacerbated by an expanding human population and pressure from tourists visiting the islands.

Conservation Actions UnderwayThe whole Galápagos Penguin population is found within the Galápagos National Park and Marine Reserve. The population is annually monitored and introduced predators are controlled by the Galápagos National Park Sevice. Research projects investigating the marine habitat use, diet, breeding activity and impact of introduced species were carried out between 2003 and 2005 (Vargas 2006, Steinfurth 2007).

Conservation Actions ProposedContinue long-term monitoring programmes. Improve fisheries management. Increase protection levels within the Galápagos Marine Reserve in areas of penguin breeding sites (fishery exclusion zones should be set up to a distance of 24 km in each direction from a colony along the coast and extending out to sea for 1.5 km). Investigate marine habitat use by non-breeding birds. Monitor and minimise effects of human disturbance in breeding areas. Monitor and minimise penguin mortality from alien species at breeding sites. Develop stronger regulations in the islands to prevent further mammalian predator introductions. Provide nest-boxes in predator-free areas to help monitor reproductive success.

Citation:

BirdLife International 2012. Spheniscus mendiculus. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 03 August 2015.